[50.02] Chandra observations of the IXO in the Starburst Galaxy NGC 3628

D.K. Strickland (JHU)

I will discuss a luminous X-ray source detected in our 52ks
Chandra ACIS-S observation of the nearby starburst galaxy
NGC 3628 which may be another intermediate-mass black hole
candidate. This source is at least ~19\arcsec \equiv 1
kpc from the nucleus of NGC 3628, has no optical, IR or
radio counterpart we can detect, has a peak 0.3-8.0 keV
X-ray luminosity of L\rm X ~5 \times 1040 erg
s-1, and is extremely variable (having changed in
luminosity by a factor > 27 over a 3 year period based on
existing ROSAT observations). This source is clearly another
example of an intermediate luminosity X-ray object (IXO),
very similar to the most-luminous X-ray source in M82 that
has attracted so much attention.

Of particular interest is that Chandra's superb spatial
resolution allows us to extract an X-ray spectrum that is
unambigously of this source alone. The ACIS-S spectrum of
the NGC 3628 IXO is best fit by a \Gamma = 1.8±0.2}
power law model, in contrast with most ASCA-based studies of
IXOs which find multi-color disk models provide better fits
to their X-ray spectra. I will briefly discuss possible
reasons for this conflict.

Dave Strickland is supported by NASA through Chandra
Postdoctoral Fellowship Award Number PF0-10012.

The author(s) of this abstract have provided an email address
for comments about the abstract:
dks@pha.jhu.edu